1. Field of the Invention
The present invention relates to a color filter and a method for manufacturing the color filter, more particularly, to a color filter and a method for manufacturing the color filter of reflective type LCD.
2. Description of the Related Art
Referring to FIG. 1, the conventional color filter 1 comprises black frame (BF) 11, a red pixel array (R) 12, a green pixel array (G) 13, a blue pixel array (B) 14 and a substrate 15. The color filter 1 for reflective type LCD is manufactured by dry film technology. Firstly, the black frame 11 is formed on the substrate 15. Then in sequence, the red pixel array 12, the green pixel array 13 and the blue pixel array 14 are formed on the substrate 15. The black frame 11, the red pixel array 12, the green pixel array 13 and the blue pixel array 14 must be formed on the substrate 15 by utilizing photomasks, exposure and development process to form the pattern of each pixel array on the substrate 15. Therefore, four photomasks are needed in the process of manufacturing the color filter 1. However, the photomask is expensive. If the number of the photomask can be lessened, the cost of the color filter will be reduced.
The red pixel array 12 is adjacent to the green pixel array 13 and the blue pixel array 14 in sequence. Because of the limit of the positioning precision of the exposure instrument, there are protrusions 16 on the adjacent area. For example, when the green pixel array 13 is formed on the substrate, the protrusion 16 is formed on the adjacent area, covering the partial edge of the red pixel array 12. Similarly, the adjacent areas between the blue pixel array 14 and the red pixel array 12 and between the blue pixel array 14 and the green pixel array 13 have the protrusions. The protrusion may easily interfere the display performance of the LCD product.
Furthermore, when the red pixel array 12, the green pixel array 13 and the blue pixel array 14 are formed on the substrate 15, the pixel array will have pinhole, if there are particles in the pixel array. The pinhole will be a white spot in the screen of the LCD, and will be a defect of the LCD product.
Therefore, it is necessary to provide an innovative and progressive color filter and method for manufacturing the same so as to solve the above problem.
One objective of the present invention is to provide a method for manufacturing a color filter. The method utilizes the dry film technology, photomasks, exposure and development process to form the black frame, the red pixel array and the green pixel array on the substrate. The blue pixel array is formed on the substrate by utilizing a back mask, exposure process from the backside of the substrate and development process. Therefore, the red pixel array and the green pixel array on the substrate can cut the UV exposure from backside. In the exposure process, only the blue pixel array in a recess area is exposed to the UV light. After the development process, the blue pixel array is formed on the substrate. Because the photomask is more expensive than the back mask, the method of the invention can reduce the cost of the LCD product by using a back mask instead of a photomask.
According to the method of the invention, the red pixel array and the green pixel array provides photomask function to shield UV from the back side of the substrate such that the blue pixel array is formed on the substrate. The problem of positioning precision and the error caused by the photomask on the prior art can be solved. Therefore, both a first adjacent area between the blue pixel array and the green pixel array and a second adjacent area between the blue pixel array and the red pixel array have flat surface without protrusions so as to have better quality.
Furthermore, according to the method of the invention, the blue pixel array is formed on the substrate by a back mask and exposure from backside. Therefore, the blue film can fill the pinhole caused by the particles on the red pixel array and the green pixel array so that the LCD product does not have the white spot caused by the pinhole. The yield of the LCD product can be improved.